The evidence-base for psychological therapy for older people is sparse compared to research for working age and young people. This often leads to therapies being intended for working age adults but delivered to older people. To ensure that the delivery of psychological therapy is applicable to the distinct and unique needs of older people, firstly, it is imperative that effectiveness of established therapies is explored specifically in this population. Secondly, it is important to understand therapy experiences and outcomes through the eyes and voices of the older people engaging in therapy. The first paper of this thesis presents a meta-analysis of the effectiveness of Acceptance and Commitment Therapy (ACT) for older people. Through a systematic literature search, 13 studies met our inclusion criteria. Methodological quality was determined using the Standard Quality Assessment Criteria (SQAC) tool. Ten studies were further included in a meta-analysis, which highlighted ACT as a promising treatment option for older people with an overall effect size of g=0.53. However, a cumulative analysis showed a variable effect for ACT in this population over time, suggesting that a true effect has yet to be established and requires further research. The second paper of this thesis explores older people’s experiences of psychological therapy. Six participants who were considered by the clinical psychologist delivering therapy to have made positive progress through therapy took part in a semi-structured interview where their experiences of therapy were explored. Interpretative Phenomenological Analysis (IPA) was used to analyse the data. Three main themes emerged which were processing my identity, the powerful therapy relationship and continuing my journey. Two sub-themes for each theme represented important convergence and divergence between participants. The findings present considerations to how therapy is delivered and subsequently received by older people and highlights how therapy outcomes may be deemed successful for this population.